Previously, the NRDC had sought to challenge the re-licensing process, arguing that so much new information about nuclear plants and the potential for accidents has been learned since the two reactors were licensed in 1985 and 1989 respectively, that it should be considered as part of the process.

It is a process filled with acronyms and the one crucial to the challenge is called SAMA, which stands for Severe Accident Mitigation Alternatives.

The NRDC most recently described SAMAs as “measures that may seriously diminish the otherwise catastrophic consequences of a severe nuclear accident at the facility, located near Philadelphia, Pennsylvania.”

The examination of SAMAs was undertaken by the NRC in 1989 and, through a series of court hearings, it was determined that new ones were not required for re-licensing.

This is not to say that NRC has ignored new science and information surrounding nuclear safety.

Many of the NRDC’s court filings have revolved around getting “standing,” or being central enough to the process that their arguments should be heard by a court, the Atomic Safety and Licensing Board or the NRC itself.

The Dec. 14 filing serves the same function.

Filed with the U.S. Court of Appeals in Washington, D.C., the filing informed the court it wants to argue that the NRC “erred” when it ruled that the environmental group could only intervene if it could obtain a waiver from the NRC, and then denied the waiver.

NRC spokesman Neil Sheehan said his agency has not yet filed a response to the NRDC’s request.

Asked for comment, Dana Melia, communications director at the plant, responded “Exelon has met all NRC requirements to obtain the extended operating licenses for Limerick Generating Station and will continue to safely operate the plant.”

According to Exelon, the Limerick plant contributes $113 million annually in direct economic impact in Pennsylvania, including $75 million in employee wages in salaries, $35 million in purchases of goods and services and $2.9 million in property tax payments.